Jack



` L July 15; 1941.

' QE. ARoN JACK 2 Sheets-Sheet l Filed Aug. 28, 1939 I 7. llllnununnn lm mw L lll/l @f/ M y;

July 15,1941.- BARON 2,249,919

JACK

Filed Aug. 28, 1939 2-Sheets-Sheetl2 Q5 y j l Patented July 15, 1941 JACK Edmund Aron, Chicago, Ill., assigner to Moto- Sway Corporationr of America, a corporation of Illinois Application August Z8, 1939-, Serial No. 292,179-

(Cl. i4- 592) 3 claims.

This invention relates to. 'jacks which are employed for the purpose of vibrating automobiles during the greasing operation. Such jacks are commonly mounted in lifting engagement. with the side frame. bars of the chassis to alternately takeV the Weight ofY the chassis and body off, and restore it to, theY springs, so as to facilitate the introduction of grease between the leaves of `the springs and to the shackle bolts and its distribution over the surfaces .to be lubricated.

Many devices of this character employ pneumatic motors for operating the jack, with complicated automatic valve mechanisms for admit-- ting andV exhausting the motive fluid and cushioning the down stroke of the jack plunger; and one object of this invention has been to get rid of such complicated and expensive mechanisms and provide a very simple and relatively inexpensive jack capable of being actuated by an ordinary electric motor. Another object has been to provide, in a jack of this type, a device having the double function of (1) assisting the motor inv effecting the lifting movement of the jack and (2) cushioning the down movement. In lthe preferred form of the invention this device comprises a tensioned spring having a forceV a manner that during the lifting operation of the jack it aids the motor, and during the lowering operation vof the jack` it opposes the gravity force '-of the load and cushions the down stroke. Preferably also the portion of the transmission gearing from the'motor tothe part acted on by the said spring is self-locking against movement under the thrust o-f the load in one direction and of the spring in the other; so that, for the lifting movement, onlyV enough power is required oi the motor'to overcome: the friction of the selflocking gearing and supplement the power of the spring, and, for the lowering movementronly enough :power is required of the motor to overcome the friction of the self-locking gearing and permit` the weight of thefload to restore the spring toits maximum tension.

AnY approved embodiment of ythe invention is illustrated in Vthe accompanying drawings, in whichv Fig. lis an elevation of the jack and its mo tor, in vertical section through the outer casing, and showing the lower end portion of the plunger.

Fig. 2 is a vertical section through the upper portion of the jack plunger, the head and saddle on the upper end ot the plunger, and the mechanism for adjusting the saddle to a fit on the part of the automobile engaged thereby; this view being a Vertical extension of the parts appearing in Fig. 1.

Fig. 3' is a verticalv axialsection, taken on the line 3-3 of Fig. 1;

Fig. 4 is a horizontaln section, taken on the line 4 4 of Fig. 3. Y

Referring tothe drawings, I0 designates an uprightfjack casing which preferably is integral With'the base support II, on which support II is mounted anv electric motor I2. The upper end of the jack casing is closed by a removable cap or cover 4I3 secured thereto by screws I4, and in and centrally of the cover I3 is fitted a bearing boss I5 fora vertically reciprocable plunger, the lower section of which is designated by I6. The lower end of the plunger sectionl I6 is secured in a ring I'l that constitutes the central portion of a cross-head I8-. The ends of the cross-head I8 are connected` by depending links I9 to a pair of cranks 20 formed in= a crank shaft 2I that is journal'led at its ends in bearings 22 carried by lateral Vbosses 23 on opposite sides of the casingv I0. Keyedon thefcrank shaft 2| is a worm gear 2.4 meshing with anddriven by a worm 25 fast on a horizontal shaft 2B journalled in the side walls' of the casing I'Ii at right angles to the axis-of the crank` shaft 2|. `Antifriction bearings 21 are preferably employed for the shaft 26, as shownin Fig. 1. One end of the shaft 26k is connected by a. coupling 23 to `the shaft of the electric motor I2.

Fromthe foregoing it will be evident that the continuous running of the motor in one direction will effect vertical reciprocations of the jack plunger.'

Depending from the cap I3 of the casing and preferably integral therewith is a hollow spring support 29, onvvthe bottom of which is stepped the lower end of va coil vspring 30. The upper end of the spring 30 bears directly on the lower side of the cross-head ring I'l, and to permit vertical,

reciprocations of the cross-head I1, the end portions I3 of the latter extend through vertical slots 3l in the opposite sides of the spring support 29V`being guideclinL said slotsv by blocks 32 on the endV portions I8 of the cross-head, which blocks slidablyy engage the walls of the slots]- The ends of the cross-head are threaded to receive nuts 33, and the portions of the casing I0 opposite the ends of the cross-head haveopenings covered Vby removable closures 34 to permit access .to the nuts 33.

In Fig. 3 the cross-head I8 is shown at the limit of its up position which corresponds to the fully raised position of the load carried by the jack. In the reverse or fully lowered position of the load, the cross-head i8 is fully lowered; and the strength of the spring 30 is such that when it is fully tensioned its force is approximately equal to the gravity force ofthe load, the spring preferably being at all times under considerable tension, which, of course, is at its maximum when the spring is fully compressed.

From the foregoing it will be seen that, assuming the jack plunger and cross-head to be at the lowermost position, when the lifting action begins the power of the motor is supplemented by the upward thrust of the fully tensioned spring 30 which is approximately equal to the weight of the load; the power given oi by the spring, of course, gradually lessening as it expands. During the lowering movement of the jack plunger and the load, the spring 30 is recompressed by the weight of the load, the only draft on the motor being to overcome the friction of the self-locking gears 24, 25. Thus, for the lifting movement, only enough poweris required of the motor to overcome the friction of the selflocking gears 24, 25 and supplement the power of the spring 30, and, for the lowering movemenlt only enough power is required of the motor to overcome the friction of the self-locking gearing and permit the weight'of the load tov restore the spring to its maximum tension. Manifestly, this means a large saving of the power output of the motor. Y

Fig. 2 illustrates a manually adjustable upper section of the jack plunger for the purpose of initially entering the same beneath the load, such as an automobile chassis bar to be lifted. Screwed onto the upper end of the lower plunger section i6 is an intermediate section 35, and telescoping within the section 35 is an upper tubular section 36. A collar 31 encircles the upper section 36, and the lower half of this collar is counter-bored to encircle the upper end of the intermediate section 35 and is secured to the latter by set screws 38. In the upper section 36 are vertically spaced holes 39, thefunction4 of which is later described. Secured von the upper end of the*v upper section 36 'is a nut 4U engaged with a threaded rod 4I that extends some'distance into i the upper end of the section 36.1 Nut 40 is nonrotatably secured to the sectionv 36` byset screwsv A head 43 has on its lower sidea'socketedlug 44 which fits over the upper end of screw` 4| and is secured to the latter by a cross pin 45. A saddle 46 is removably mounted on the head 43, the saddle having a central depending lug 41 fitting into a central socket 48 in the head 43,4

and lateral lugs 49 on each side thereof that are straddled by upstanding lugs 56 on the ends of the head 43. l

Encircling the upper tubular plunger section 36 is the hub 5i of a hand wheel 52, said hub being formed with a depending integral annular positely disposed vertical slots 56 through which and one of the holes 39 is inserted a locking pin 51. This pin 51 locks the hand wheel to the upper tubular plunger section 36, and, since the nut is non-rotatably mount-ed on the upper end of the plunger section 36, and the upper end of the screw 4| is non-rotatably engaged with the head 43, rotation of the hand wheel 52 raises or lowers the head and saddle. This is to obtain a nal fine adjustment of the saddle with the chassis frame, vehicle spring, or other part engaged thereby. A preliminary lcoarse adjustment is readily effected by withdrawing pin 51, grasping the nut 4U and bodily raising or lowering the plunger section 36 until another hole 39 registers with the slots 56, and then reinserting the pin 51. The last above described means for lengthening or shortening the plunger to adapt its upper end to a fit on the part to be lifted, is shown, described and claimed in my co-pending application on a combined vehicle lifting and rocking device, Serial No. 270,382, filed April 27, 1939, and no claim thereto is made herein.

Modicationsand chang-es f. of the details of structure and arrangement may be resorted to within the scope and coverage of the appended claims, withoutdeparting from the principle of the 'invention-or sacrificing any ofthe advantages thereof.

I claim:

1. In a jack ofthe class described, the combination with a casing having a cap, and a vertical plunger extending through and guided by said cap, of a spring support depending from said cap, a cross-head extending across said spring support and secured to said plunger, an electric motor and a power transmission means from said motor to said cross-head for reciprocating the latter, and a tensioned coil spring having a force when fully tensioned approximately equal to the gravity force of the loadraised by the jack, said spring being stepped on said spring support with its upper end in thrust engagement with said cross-head.

2. In a jack of the class described, the combination with a casing having a cap, and a vertical plunger extending through and guided by Said cap, of a spring support depending from said cap, a cross-head extending across said` spring support and secured to said plunger, a crank shaft journaled vin and between the sides of said casing below said spring support, linksV connecting said crank shaft with said cross-head, a worm'wheelvfast on said crank shaft, a worm in driving engagement with said worm wheel, an electric motor driving said Worm, and a. tensioned coil spring having a'force whenfully ten'- sioned approximately equal to the gravity force of the load raised by the jack, said spring being stepped on said spring support with its upper end in thrust engagement with said cross-head. 3. A specific embodiment of the combination dened in claim 2, wherein the spring support is formed with vertical slots in its opposed side walls, the cross-head extends through and is guided by said slots, and the links are connected to the end portions of the cross-head on the outer sides of said slots.

, EDMUND ARON. 

